of smaller political groups.

The other institution is a social development. It is the olag,
an institution of trial marriage. It is not known to exist among
adjoining people, but is found throughout the area in which the
intugtukan exists; they are apparently coextensive. I was repeatedly
informed that the olag is not found in the Banawi area south of Bontoc,
or in the Tinglayan area east, or among the Tinguian to the north,
or in Benguet far southwest, or in Lepanto immediately southwest --
though I have some reason to believe that both the intugtukan and
olag exist in a crumbling way among certain Lepanto Igorot.

Besides these two institutions there are other differing marks of
culture between the Bontoc area and adjoining people. Some of these
were suggested a few pages back, others will appear in following pages.

Without doubt the limits of the spread of the common culture have
been determined mainly by the physiography of the country. One of the
two pueblos in the area not on the common drainage system is Lias,
but Lias was largely built by a migration from Bontoc pueblo -- the
hotbed of Bontoc culture. Barlig, the other pueblo not on the common
drainage system (both Barlig and Lias are on the Sibbu River), lies
between Lias and the other pueblos of the Bontoc culture area, and so
naturally has been drawn in line and held in line with the culture
of the geographic area in which it is located -- its institutions
are those of its environment.


The Bontoc man